As shown in FIG. 1, standard overhead projectors 1, which have been used for many years, project images from a thin transparent plastic sheet to a screen 2. Projector 1 includes a base 1a, housing a light source, and a lens 1b. The transparency is placed on top of base 1a where light emitted from the light source shines through the transparency. Lens 1b directs the image to screen 2. A disadvantage of a standard overhead projection system is that it cannot interface with a computer. The system transmits only the image printed on the transparency. Other disadvantages of standard overhead projection system are that it is too heavy to be easily portable, it produces a lot of heat, and it consumes a lot of power.
Other overhead projector systems in use today, however, are capable of interfacing with computers. One such projector system in use today is the BARCO Data 600 manufactured by BARCO Projection Systems and shown in prior art FIG. 2. The BARCO data 600 3 uses three monochrome CRT (Cathode Ray Tube) projection tubes 4, each projecting a red, green or blue image which is converged by use of colored lenses to create a color picture on screen 5. Projection system 3 can be interfaced to a computer (not shown), allowing the images displayed on the computer's CRT to also be displayed on screen 5. Disadvantages of this type of projection system are that it is not portable, and it is large because of the physical depth required by the CRT technology.
What is needed is a projection system which uses less power and generates less heat, but also interfaces to computers, is capable of displaying multimedia images, and is portable.